Denote the elements of the field F₄ by {0, 1, w, w + 1}, where w satisfies the following equation with coefficients in F₂: w² + w + 1 = 0. Dragonul is a recurrent double sequence defined by a(i, 0) = a(0, j) = 1 and a(i, j) = f(a(i, j-1), a(i-1, j-1), a(i-1, j)), where f(x, y, z ) = x² + w x + (w + 1) y² + w y + w z. This recurrent double sequence can be also obtained using a system of substitutions of type 2 -> 4 with 32 rules.

The system of substitutions is too large to be presented here.